Noise suppressed,multifocus image fusion for enhanced intraoperative navigation

Current intraoperative imaging systems are typically not able to provide ‘sharp’ images over entire large areas or entire organs. Distinct structures such as tissue margins or groups of malignant cells are therefore often difficult to detect, especially under low signal‐to‐noise‐ratio conditions. In this report, we introduce a noise suppressed multifocus image fusion algorithm, that provides detailed reconstructions even when images are acquired under sub‐optimal conditions, such is the case for real time fluorescence intraoperative surgery. The algorithm makes use of the Anscombe transform combined with a multi‐level stationary wavelet transform with individual threshold‐based shrinkage. While the imaging system is integrated with a respiratory monitor triggering system, it can be easily adapted to any commercial imaging system. The developed algorithm is made available as a plugin for Osirix. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Image fusion for dynamic contrast enhanced magnetic resonance imaging

Background  

Multivariate imaging techniques such as dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) have been shown to provide valuable information for medical diagnosis. Even though these techniques provide new information, integrating and evaluating the much wider range of information is a challenging task for the human observer. This task may be assisted with the use of image fusion algorithms.     

Sonobioreactors: using ultrasound for enhanced microbial productivity

Enhanced metabolic productivity of microbial, plant and animal cells in bioreactors can greatly improve the economics of biotechnology processes. Ultrasound is one method of intensifying the performance of live biocatalysts. Ultrasonication is generally associated with damage to cells but evidence is emerging for beneficial effects of controlled sonication on conversions catalyzed by live cells. This review focuses on the productivity enhancing effects of ultrasound on live biological systems and the design considerations for sonobioreactors required for ultrasound-enhanced biocatalysis.     

Bone measurement by enhanced contrast image analysis: ovariectomized and intact Macaca fascicularis as a model for human postmenopausal osteoporosis

This paper presents an image enhancement and analysis system (DARWIN) based on an inexpensive microcomputer and applies the system to two bone morphometry problems relevant to postmenopausal osteoporosis. Using ovariectomized and intact female Macaca fascicularis as a model, we examined the radiodensity of the sixth lumbar vertebra and the cross-section area of the right femur. Significantly lower bone density was observed in the vertebral segments of the ovariectomized animals. No significant differences were observed in comparisons of the femoral cross sections. The reduction in radiographic density of the ovariectomized animals' vertebrae is similar to that observed in postmenopausal women, supporting the use of female cynomolgus macaques as models of bone loss in postmenopausal osteoporosis.     

Comparison of SUMO fusion technology with traditional gene fusion systems: enhanced expression and solubility with SUMO

Despite the availability of numerous gene fusion systems, recombinant protein expression in Escherichia coli remains difficult. Establishing the best fusion partner for difficult-to-express proteins remains empirical. To determine which fusion tags are best suited for difficult-to-express proteins, a comparative analysis of the newly described SUMO fusion system with a variety of commonly used fusion systems was completed. For this study, three model proteins, enhanced green fluorescent protein (eGFP), matrix metalloprotease-13 (MMP13), and myostatin (growth differentiating factor-8, GDF8), were fused to the C termini of maltose-binding protein (MBP), glutathione S-transferase (GST), thioredoxin (TRX), NUS A, ubiquitin (Ub), and SUMO tags. These constructs were expressed in E. coli and evaluated for expression and solubility. As expected, the fusion tags varied in their ability to produce tractable quantities of soluble eGFP, MMP13, and GDF8. SUMO and NUS A fusions enhanced expression and solubility of recombinant proteins most dramatically. The ease at which SUMO and NUS A fusion tags were removed from their partner proteins was then determined. SUMO fusions are cleaved by the natural SUMO protease, while an AcTEV protease site had to be engineered between NUS A and its partner protein. A kinetic analysis showed that the SUMO and AcTEV proteases had similar KM values, but SUMO protease had a 25-fold higher kcat than AcTEV protease, indicating a more catalytically efficient enzyme. Taken together, these results demonstrate that SUMO is superior to commonly used fusion tags in enhancing expression and solubility with the distinction of generating recombinant protein with native sequences.     

Luciferase-YFP fusion tag with enhanced emission for single-cell luminescence imaging

Taking advantage of the phenomenon of bioluminescence resonance energy transfer (BRET), we developed a bioluminescent probe composed of EYFP and Renilla reniformis luciferase (RLuc)--BRET-based autoilluminated fluorescent protein on EYFP (BAF-Y)--for near-real-time single-cell imaging. We show that BAF-Y exhibits enhanced RLuc luminescence intensity and appropriate subcellular distribution when it was fused to targeting-signal peptides or histone H2AX, thus allowing high spatial and temporal resolution microscopy of living cells.     

The application of ultrasound in neuroendoscopic procedures: first results with the new tool "NECUP-2"

In this paper, our experience with originally constructed Neurosurgical Endoscopic Contact Ultrasound Probe "NECUP-2" in neuroendoscopy is reported. Between June 1997 and June 2007, 132 neuroendoscopic procedures have been performed: 102 endoscopic thrid ventriculostomies (ETV), 15 arachnoid cysts and 5 intraventricular tumours operations. The "NECUP-2" was applied effectively in all cases in which blunt perforation was not possible: 38/102 ETY, 10/10 septostomies, 15/15 arachnoid cysts. In five cases of intraventricular tumours, neuroendoscopic procedure was combined with open microsurgery for tumour removal with preservation of vascular structures. There were no "NECUP-2" related complications. Of postoperative complications, we had liquorrhea (9 patients), and symptoms of meningitis (6 patients). In the follow-up period (6 months to 6 years), we had a patency rate of 80% (50/63 patients). All patients improved in clinical status. According to the first results, it seems that ultrasonic contact probe NECUP-2 presents a new device in neurosurgical armamentarium that can be used in various fields of neurosurgery. With minimal and controlled lesion that is produced at the tip of the probe, it can be used in highly demanding operations such as third ventriculostomy and tumour resection.     

Melatonin in epilepsy: first results of replacement therapy and first clinical results

At a single evening dose of 5-10 mg, melatonin (MLT), the pineal gland hormone, can exert a positive effect on the frequency of epileptic attacks in children with sleep disturbances of various etiologies. We have shown that the sleep behavior can be normalized and an existing epilepsy can be favorably influenced. Pretherapeutic MLT secretion profiles can provide new information concerning the origin and treatment of these disturbances. In vitro experiments suggest that this effect might be the result of the interaction between MLT and MLT-specific receptors in the neocortex. Due to its favorable safety profile, MLT can be liberally administered in the specified doses and be considered as a useful antiepileptic drug.     

Targeted contrast agents for magnetic resonance imaging and ultrasound

The development of contrast agents that can be localized to a particular tissue or cellular epitope will potentially allow the noninvasive visualization and characterization of a variety of disease states. Recent advances have been made in the field of molecular imaging with magnetic resonance imaging and ultrasound and varied approaches have been devised to overcome the high background tissue signal. The types of agents and applications developed include gadolinium-conjugated targeting molecules for imaging of fibrin, superparamagnetic iron oxide particles for stem-cell tracking, multimodal perfluorocarbon nanoparticles for visualization of angiogenesis, liposomes for targeting atheroma components, and microbubbles for imaging transplant rejection.     

Cellular damage and apoptosis along with changes in NF-kappa B expression were induced with contrast agent enhanced ultrasound in gastric cancer cells and hepatoma cells

Background

Anticancer research resulted in the discovery of a promising antimitotic metabolite, 2-methoxyestradiol. 2-Methoxyestradiol-bis-sulphamate, a bis-sulphamoylated analogue exerts antiproliferative- and antimitotic activity. Investigating the anticancer potential of 2-methoxyestradiol-bis-sulphamate requires demonstrating the influence of 2-methoxyestradiol-bis-sulphamate on non-tumorigenic cells. This project focused on the in vitro effects of 2-methoxyestradiol-bis-sulphamate on the non-tumorigenic MCF-12A breast epithelial cell line.

Methods

The in vitro influence of 2-methoxyestradiol-bis-sulphamate was investigated on cell cycle progression, possible induction of apoptosis and autophagy and reactive oxygen species generation. Cell cycle progression was done using flow cytometry in conjunction with ethanol fixation and propidium iodide staining. Displaying effects on the mitochondrial membrane potential was achieved utilizing flow cytometry and the MitoCapture ^TM Mitochondrial apoptosis detection kit. Autophagy detection was done by means of flow cytometry and anti-LC3B conjugated to DyLight 488. Reactive oxygen species generation was conducted employing flow cytometry and 2,7-dichlorofluorescein diacetate and hydroethidine.

Results

This study demonstrated that 2-methoxyestradiol-bis-sulphamate did not affect cell cycle progression or reactive oxygen species in a statistically significant manner in the non-tumorigenic MCF-12A cell line. In addition, 2-methoxyestradiol-bis-sulphamate did not statistically significantly induce apoptosis or autophagy.

Conclusion

Reports indicate that 2-methoxyestradiol-bis-sulphamate induces apoptosis and autophagy in several tumorigenic cell lines. The anticancer ability of 2-methoxyestradiol-bis-sulphamate is due to its antimitotic activity. However, this study demonstrates the promising notion that 2-methoxyestradiol-bis-sulphamate does not affect the non-tumorigenic MCF-12A cells. This project contributes to the embedded scientific knowledge regarding the differential death mechanisms used by 2-methoxyestradiol-bis-sulphamate on tumorigenic and non-tumorigenic cell lines.     

Minimal aggregate size and minimal fusion unit for the first fusion pore of influenza hemagglutinin-mediated membrane fusion

The data of Melikyan et al. (J. Gen. Physiol. 106:783, 1995) for the time required for the first measurable step of fusion, the formation of the first flickering conductivity pore between influenza hemagglutinin (HA) expressing cells and planar bilayers, has been analyzed using a new mass action kinetic model. The analysis incorporates a rigorous distinction between the minimum number of HA trimers aggregated at the nascent fusion site (which is denoted the minimal aggregate size) and the number of those trimers that must to undergo a slow essential conformational change before the first fusion pore could form (which is denoted the minimal fusion unit). At least eight (and likely more) HA trimers aggregated at the nascent fusion site. Remarkably, of these eight (or more) HAs, only two or three must undergo the essential conformational change slowly before the first fusion pore can form. Whether the conformational change of these first two or three HAs are sufficient for the first fusion pore to form or whether the remaining HAs within the aggregate must rapidly transform in a cooperative manner cannot be determined kinetically. Remarkably, the fitted halftime for the essential HA conformational change is roughly 10(4) s, which is two orders of magnitude slower than the observed halftime for fusion. This is because the HAs refold with distributed kinetics and because the conductance assay monitored the very first aggregate to succeed in forming a first fusion pore from an ensemble of hundreds or thousands (depending upon the cell line) of fusogenic HA aggregates within the area of apposition between the cell and the planar bilayer. Furthermore, the average rate constant for this essential conformational change was at least 10(7) times slower than expected for a simple coiled coil conformational change, suggesting that there is either a high free energy barrier to fusion and/or very many nonfusogenic conformations in the refolding landscape. Current models for HA-mediated fusion are examined in light of these new constraints on the early structure and evolution of the nascent fusion site. None completely comply with the data.     

Augmenting intraoperative ultrasound with preoperative magnetic resonance planning models for percutaneous renal access

ABSTRACT: BACKGROUND: Ultrasound (US) is a commonly-used intraoperative imaging modality for guiding percutaneous renal access (PRA). However, the anatomy identification and target localization abilities of the US imaging are limited. This paper evaluates the feasibility and efficiency of a proposed image-guided PRA by augmenting the intraoperative US with preoperative magnetic resonance (MR) planning models. METHODS: First, a preoperative surgical planning approach is presented to define an optimal needle trajectory using MR volume data. Then, a MR to US registration is proposed to transfer the preoperative planning into the intraoperative context. The proposed registration makes use of orthogonal US slices to avoid local minima while reduce processing time. During the registration, a respiratory gating method is used to minimize the impact of kidney deformation. By augmenting the intraoperative US with preoperative MR models and a virtual needle, a visual guidance is provided to guarantee the correct execution of the surgical planning. The accuracy, robustness and processing time of the proposed registration were evaluated by four urologists on human data from four volunteers. Furthermore, the PRA experiments were performed by the same four urologists on a kidney phantom. The puncture accuracy in terms of the needle-target distance was measured, while the perceptual quality in using the proposed image guidance was evaluated according to custom scoring method. RESULTS: The mean registration accuracy in terms of the root mean square (RMS) target registration error (TRE) is 3.53mm. The RMA distance from the registered feature points to their average is 0.81mm. The mean operating time of the registration is 6'4". In the phantom evaluation, the mean needle-target distance is 2.08mm for the left lesion and 1.85mm for the right one. The mean duration for all phantom PRA tests was 4'26". According to the custom scoring method, the mean scores of the Intervention Improvement, Workflow Impact, and Clinical Relevance were 4.0, 3.3 and 3.9 respectively. CONCLUSIONS: The presented image guidance is feasible and promising for PRA procedure. With careful setup it can be efficient for overcoming the limitation of current US-guided PRA.     

Visual navigation in starfish: first evidence for the use of vision and eyes in starfish

Most known starfish species possess a compound eye at the tip of each arm, which, except for the lack of true optics, resembles an arthropod compound eye. Although these compound eyes have been known for about two centuries, no visually guided behaviour has ever been directly associated with their presence. There are indications that they are involved in negative phototaxis but this may also be governed by extraocular photoreceptors. Here, we show that the eyes of the coral-reef-associated starfish Linckia laevigata are slow and colour blind. The eyes are capable of true image formation although with low spatial resolution. Further, our behavioural experiments reveal that only specimens with intact eyes can navigate back to their reef habitat when displaced, demonstrating that this is a visually guided behaviour. This is, to our knowledge, the first report of a function of starfish compound eyes. We also show that the spectral sensitivity optimizes the contrast between the reef and the open ocean. Our results provide an example of an eye supporting only low-resolution vision, which is believed to be an essential stage in eye evolution, preceding the high-resolution vision required for detecting prey, predators and conspecifics.     

Diffusion kurtosis imaging in head and neck cancer: A correlation study with dynamic contrast enhanced MRI

PurposeTo investigate the biophysical meaning of Diffusion Kurtosis Imaging (DKI) parameters via correlations with the perfusion parameters obtained from a long Dynamic Contrast Enhanced MRI scan, in head and neck (HN) cancer.MethodsTwenty two patients with newly diagnosed HN tumor were included in the present retrospective study. Some patients had multiple lesions, therefore a total of 26 lesions were analyzed. DKI was acquired using 5b values at 0, 500, 1000,1500 and 2000 s/mm². DCE-MRI was obtained with 130 dynamic volumes, with a temporal resolution of 5 s, to achieve a long scan time (>10 min). The apparent diffusion coefficient D_app and apparent diffusional kurtosis K_app were calculated voxel-by-voxel, removing the point at b value = 0 to eliminate possible perfusion effects on the parameter estimations. The transfer constants K^trans and K_ep, v_e, and the histogram-based entropy (En) and interquartile range (IQR) of each DCE-MRI parameter were quantified. Correlations between all variables were investigated by the Spearman’s Rho correlation test.ResultsModerate relationships emerged between D_app and K_ep (Rho =  − 0.510, p = 0.009), and between D_app and v_e (Rho = 0.418, p = 0.038). En(K_ep) was significantly related to K_app (Rho = 0.407, p = 0.043), while IQR(K_ep) showed an inverse association with D_app (Rho = -0.422, p = 0.035).ConclusionsA weak to intermediate correlation was found between DKI parameters and both K_ep and v_e. The kurtosis was associated to the intratumoral heterogeneity and complexity of the capillary permeability, expressed by En(K_ep).